1. Field of the Invention
The present disclosure generally relates to a toner supply roller of an electrophotographic imaging apparatus capable of improved toner chargeability and toner supply so that an image is produced with increased resolution, and to methods for preparing the same.
2. Description of the Related Art
An electrophotographic image forming apparatus such as a laser printer, a facsimile, or a copier generally employs a toner supply roll, a photosensitive medium, a charging roller, a developing roller, and a transfer roller formed around the photosensitive medium. With such an arrangement, a developing agent, supplied from a developing device, is transported by the voltage supplied to the photosensitive medium, the charging roller, the developing roller or the transfer roller, to form a predetermined image onto a printing medium. By way of an example, the charging roller charges a surface of the photosensitive medium with a predetermined voltage, on which surface an electrostatic latent image is formed when the charged surface is exposed to light modulated according to the print data that is emitted from a light exposure unit. The developing roller supplies developing agent to the photosensitive medium to visualize the electrostatic latent image into a developer image. The developer image is transferred by the transfer roller onto the printing medium passing between the photosensitive medium and the transfer roller.
The developing roller must have enough transfer characteristics and resiliency in order to contact the photosensitive medium and attach toner onto the electrostatic latent image. A non-magnetic mono-component developer is widely used to develop the electrostatic latent image. However, due to the difficulty in controlling the charge of the toner on the developing roller, problems such as non-uniform charge or unstable charging operation may occur. These problems may generate image defects such as ghosts. It is particularly difficult to obtain high quality images with high optical density in high temperature and humid environments.